一种雷达非线性调频信号检测及仿真方法

摘要

由于雷达非线性调频(NLFM)信号的时频非线性分布特性,常规检测算法难以实现信号能量的有效聚集,传统采用NLFM信号检测时准确率较低,在低信噪比下甚至会失效.针对上述问题,应用了一种基于广义时宽-带宽积的最优窗函数,提出了一种改进的短时分数阶傅立叶变换瞬时频率估计算法.应用改进算法可有效提高非线性调频信号的检测性能,提高检测的准确率.仿真结果表明,在相同信噪比下,提出的方法对NLFM信号的检测概率高于传统方法,性能较好.%Because of radar nonlinear frequency—modulated signals' nonlinear time-frequency distribution characteristics , conventional detection algorithms can hardly gather signals' energy. The accuracy rate is low when it is used to detect NLFM signals, even it fails in low SNR. For this problem, an optimal window function based on the generalized time—bandwidth product was used, and an instantaneous frequency estimation algorithm base on improved short-time fractional fourier transform was proposed. This can effectively improve the detection performance of the NLFM signals and improve the accuracy rate. The simulation results show that, the proposed algorithm has a higher accuracy rate than traditional algorithms when used to detect NLFM signals and anti—jamming at the same SNR.